If you want to maximize your fitness results, a heart rate monitor could be the cheapest personal trainer you ever “hire.” A heart rate monitor is a simple, efficient tool that monitors intensity and helps you create an individualized training program that is customized to fit your body and needs. Some people don’t exercise hard enough, while others exercise too hard—a heart rate monitor takes the mystery out of the process.
Aerobic versus Anaerobic Exercise
Unless you are a professional athlete, you don’t need to understand the complicated science of exercise. You only need to know the basics. In order to build fitness, you want to spend most of your time exercising aerobically rather than anaerobically.
- Aerobic exercise refers to the body’s fat-burning capability. An example of aerobic exercise is a long, slow bike ride at a comfortable pace where you can talk.
- Anaerobic exercise refers to the body’s sugar-burning capability. An example of anaerobic exercise is a sprint to the finish at the end of a bike race.
Believe it or not, most people spend way too much time in anaerobic training zones, which results in overtraining—and becoming less fit instead of more fit. (See The Pitfalls of Overtraining.)
How Do You Know if You Are Training Aerobically or Anaerobically?
You may have heard people referring to their “target heart zone.” There are actually five true heart rate training zones (see chart below), but most people refer to the aerobic training zone as the “target heart zone” because that’s the one where we should spend the majority of our time.
By exercising in an aerobic heart zone, you teach your body to choose fat as its fuel source. The Maximum Aerobic Heart Rate is the heart rate at which you get the maximum aerobic benefits with the least amount of anaerobic stimulation. (For most people this is 80%.) When you train below this ceiling, you are actually training your body to choose fat as its fuel source (over glucose) and teaching it to use oxygen more efficiently.
The average exerciser who wants to increase fitness and lose weight should spend the majority of their exercise time between 65-80% of their maximum heart rate. Most people really only need to focus on three zones (based on a simplified version of the five zones).
A good rule of thumb is to look at your workouts for the week and plan to spend:
- 70% of your time in your target zone (which we are calling 65-80%)
- 10% above it (working harder at Anaerobic Threshold; sprints, intervals)
- 20% below it (warm up and recovery)
Benefits of Training Aerobically
There are many benefits to exercising in the aerobic heart zone (below 80%):
- Heart size increases (can pump more blood so heart doesn’t work as hard)
- Decrease in exercise heart rate
- Decrease in resting heart rate
- Increase in oxygen uptake in muscle fibers
- Increase in capillarization (builds more capillaries)
- Increase in fat utilization
It’s important to note that none of this happens when you exercise in the anaerobic zone. If you want to see the best results from your exercise, stick to a moderate (aerobic) intensity to get the most bang for your buck. To learn more, see Get Intense and Finding Your Heart Rate Training Zone.